how to unite strings in php code example

Example 1: join string php

<?php
$arr = array('Hello','World!','Beautiful','Day!');
echo join(" ",$arr);
?>

Example 2: php glue strings

<?php
$a = "Hello ";
$b = $a . "World!"; // now $b contains "Hello World!"

$a = "Hello ";
$a .= "World!";     // now $a contains "Hello World!"
?>